1. Field of the Invention
The invention relates to a wood planing machine, more particularly to a portable wood planing machine provided with improvements relating to a cutter unit and an indicator for indicating a thickness that will be removed from a workpiece by the cutter unit.
2. Description of the Related Art
Various forms of wood planing machines have existed in the art. FIG. 1 shows a portable planing machine 10 which is disclosed in U.S. Pat. No. 5,771,949. The planing machine 10 has an upper carriage 11 which is mounted on a lower base 12 via pairs of upstanding posts (not shown) and which is slidable along the posts to move upward and downward. As shown in FIG. 2, the carriage 11 carries a cutter support 131 rotated by a belt 132. A workpiece planing cutter 133 is secured to the cutter support 131 via a press plate 135 which is screwed to the cutter support 131 via screws 134 and which clamps the cutter 133 against the cutter support 131.
In order to indicate the thickness to be removed from a workpiece by the cutter 133, the carriage 11 is further provided with an indicator 16 which has a pointer 161 and a workpiece contact element 162. As best shown in FIG. 3, the pointer 161, which is pivotally mounted on the carriage 11, is connected to the workpiece contact element 162 to project downward from the carriage 11. The pointer 161 is provided with a pointing end extending to a graduated member 163. The pointing end is normally set at "zero" of the graduations on the graduated member 163. When a workpiece is fed in between the carriage 11 and the base 12, the workpiece contact element 162 will be pushed upward by the workpiece, thereby moving the pointing end upward to a graduation that indicates a thickness that will be removed from the workpiece by the planing cutter 133.
One of the problems encountered in the above-mentioned arrangement of the planing machine 10 is that assembly of the cutting element 133 is laborious due to the need to handle several screws and to align screw holes of the press plate 135 with those of the cutting element 133 and the cutter support 131. Another problem thereof resides in the workpiece contact element 162 which has a wide contact part to contact the workpiece when the workpiece is fed. As the surface of the workpiece to be processed is generally not smooth, it may drag the contact element 162 while moving under the carriage, thereby moving the contact element 162 away from a proper position and affecting adversely the performance of the pointer 161. In case the contact element 162 sticks to the workpiece, it may run the risk of becoming damaged.
FIG. 4 shows another conventional planning cutter unit 30 which comprises a substantially cylindrical cutter seat 31 having two cutter receiving grooves 32 to receive two cutting elements 35 (only one is shown), respectively. A press plate 36 with screws 37 is disposed in each groove 32 to press each cutting element 35 against the wall of the groove 32. Resilient members 34 are disposed in holes 33 provided in a groove bottom of each groove 32 to support resiliently the cutting element 35. In this cutter unit 30, although assembly of the cutting elements 35 is facilitated, the resilient members 34 may have different compressible characteristics so that the cutting elements 35 resting thereon may have their cutting edges placed out of a proper orientation relative to the cutter seat 31. In this situation, it is necessary to correct the position of the cutting elements 35 by using a tool with one hand during the process of tightening the screws to pressurise the press plate 36. Thus, the cutter unit 30 is inconvenient for assembly or replacement of the cutting element 35.